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Commit e2346677 authored by Dan Williams's avatar Dan Williams
Browse files

dmaengine: advertise all channels on a device to dma_filter_fn 



Allow dma_filter_fn routines to disambiguate multiple channels on a device
rather than assuming that all channels on a device are equal.

Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Reported-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 864498aa

drivers/dma/dmaengine.c

+13 −20
Original line number Diff line number Diff line
@@ -454,10 +454,10 @@ static void dma_channel_rebalance(void) 
		}

}



static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev)

static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev,

					  dma_filter_fn fn, void *fn_param)

{

	struct dma_chan *chan;

	struct dma_chan *ret = NULL;



	if (!__dma_device_satisfies_mask(dev, mask)) {

		pr_debug("%s: wrong capabilities\n", __func__);
@@ -479,11 +479,15 @@ static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_devic 
				 __func__, dma_chan_name(chan));

			continue;

		}

		ret = chan;

		break;

		if (fn && !fn(chan, fn_param)) {

			pr_debug("%s: %s filter said false\n",

				 __func__, dma_chan_name(chan));

			continue;

		}

		return chan;

	}



	return ret;

	return NULL;

}



/**
@@ -496,22 +500,13 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v 
{

	struct dma_device *device, *_d;

	struct dma_chan *chan = NULL;

	bool ack;

	int err;



	/* Find a channel */

	mutex_lock(&dma_list_mutex);

	list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {

		chan = private_candidate(mask, device);

		if (!chan)

			continue;



		if (fn)

			ack = fn(chan, fn_param);

		else

			ack = true;



		if (ack) {

		chan = private_candidate(mask, device, fn, fn_param);

		if (chan) {

			/* Found a suitable channel, try to grab, prep, and

			 * return it.  We first set DMA_PRIVATE to disable

			 * balance_ref_count as this channel will not be
@@ -529,11 +524,9 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v 
				       dma_chan_name(chan), err);

			else

				break;

		} else

			pr_debug("%s: %s filter said false\n",

				 __func__, dma_chan_name(chan));

			chan = NULL;

		}

	}

	mutex_unlock(&dma_list_mutex);



	pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",